package com.aliwo.interceptor;

import com.aliwo.model.ResultResponse;
import com.aliwo.utils.JWTUtils;
import com.google.gson.Gson;
import io.jsonwebtoken.Claims;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * 用户登录拦截器. 在进入controller之前执行拦截器方法
 *
 * @author Xu Yayuan
 * @date 2021/11/3
 */
public class LoginIntercepter implements HandlerInterceptor {

    private static final Gson gson = new Gson();

    /**
     * 进入controller之前进行拦截
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 从请求头获取token
        String token = request.getHeader("token");
        if (null == token) {
            // 从请求参数中获取token
            token = request.getParameter("token");
        }
        if (null != token) {
            // 校验token
            Claims claims = JWTUtils.checkJWT(token);
            if (null != claims) {
                Integer userId = (Integer) claims.get("id");
                String name = (String) claims.get("name");
                request.setAttribute("user_id", userId);
                request.setAttribute("name", name);
                return true;
            }
        }
        sendJsonMessage(response, ResultResponse.buildError("请登录"));
        return false;
    }

    /**
     * 响应数据给前端
     */
    public static void sendJsonMessage(HttpServletResponse response, Object obj) throws IOException {
        response.setContentType("application/json; charset=utf-8");
        PrintWriter writer = response.getWriter();
        writer.print(gson.toJson(obj));
        writer.close();
        response.flushBuffer();
    }


}
